Roughness and spatial density judgments on visual and haptic textures using virtual reality (original) (raw)
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2010
This paper reports the results of an experimental study on the perception of rough textures in virtual environments. The experiment is conducted with a haptic tactile actuator that provides sensations of rough textures directly to the fingertip of the users. It consists of a brush and a DC motor. The brush rubs directly against the user's fingertip. The speed and direction of the brush are varied to control the roughness of the virtual surface in an attempt to determine the effect of either variable on perceived roughness. The actuator is designed to be augmented with an existing force feedback device to create a package that provides both force feedback and tactile feedback. The aim of the experiment is to determine the magnitudes of rough textures that can be achieved through this device by comparing the virtual textures with real sandpapers of different grit sizes. The results show that although each subject's perception of roughness is biased using various sandpapers, the data is divided between two trends. One group of users perceives the roughness to increase with increasing speed while the other group perceives the roughness to decrease. Between both groups, the results do not show any significant effect of direction of rotation.
The physical basis of perceived roughness in virtual sinusoidal textures
IEEE transactions on haptics
Using a high-fidelity haptic interface based on magnetic levitation, subjects explored virtual sinusoidal textures with a frictionless probe and reported the subjective magnitude of perceived roughness. A psychophysical function was obtained spanning 33 levels of spatial periods from 0.025 to 6.00 mm. Kinematic and dynamic variables were recorded at 1,000 Hz and used to derive a set of variables to correlate with the psychophysical outcome. These included position, velocity, kinetic energy, instantaneous force (based on acceleration), mean force, and variability of the z-axis force signal from the power spectral density. The analysis implicates power of the force signal as the physical correlate of perceived roughness of sinusoidal textures. The relationship between power and roughness held across the range of spatial periods examined.
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We describe experiments that compared the perceived relative roughness of textured virtual walls synthesized with an accurately controlled haptic interface. Texture was modeled as a spatially modulated sinusoidal friction grating. The results indicate that both the modulation depth of the grating (A), and the coefficient of friction (µ) are strongly associated with the perceived roughness when increasing either A or µ. Changing the spatial period of the grating (l), however, did not yield consistent relative roughness judgement results, indicating that there is a weaker association.
Cerebral cortex (New York, N.Y. : 1991), 2014
Perceived roughness is associated with a variety of physical factors and multiple peripheral afferent types. The current study investigated whether this complexity of the mapping between physical and perceptual space is reflected at the cortical level. In an integrative psychophysical and imaging approach, we used dot pattern stimuli for which previous studies reported a simple linear relationship of interdot spacing and perceived spatial density and a more complex function of perceived roughness. Thus, by using both a roughness and a spatial estimation task, the physical and perceived stimulus characteristics could be dissociated, with the spatial density task controlling for the processing of low-level sensory aspects. Multivoxel pattern analysis was used to investigate which brain regions hold information indicative of the level of the perceived texture characteristics. While information about differences in perceived roughness was primarily available in higher-order cortices, th...
The perceived roughness of resistive virtual textures
ACM Transactions on Applied Perception, 2006
In previous work, we demonstrated that people reliably perceive variations in surface roughness when textured surfaces are explored with a rigid link between the surface and the skin [e.g., Klatzky and Lederman 1999; Klatzky et al. 2003]. Parallel experiments here investigated the potential of a force-feedback mouse to render surfaces varying in roughness. The stimuli were surfaces with alternating regions of high and low resistance to movement in the x (frontal) dimension (called ridges and grooves, respectively). Experiment 1 showed that magnitude ratings of roughness varied systematically with the spatial period of the resistance variation. Experiments 2 and 3 used a factorial design to disentangle the contributions of ridge and groove width. The stimuli constituted eight values of groove width at each of five levels of ridge width (Experiment 2) or the reverse (Experiment 3). Roughness magnitude increased with ridge width while remaining essentially invariant over groove width. ...
Virtual Tactile Simulation: A Novel Display and the Effects on Users’ Texture Perception
ASME/ISCIE 2012 International Symposium on Flexible Automation, 2012
This paper presents a novel study on the simulation of material texture by means of electro-tactile stimuli and details the effects on the users' ability to recognize and discriminate different material classes. The research exploits a novel tactile display to simulate material texture and validates the adopted simulation strategy by experimental testing. The tactile system elaborates data from real material samples and combines electrical stimuli and mechanical vibration to reproduce both roughness and texture coarseness sensations. Then, an experimental protocol based on the theory of Psychophysics is defined to carry out system calibration and tests with users. The research aims at validating the proposed simulation strategy and checking the user response on virtual tactile stimuli. Experimentations were carried out to reproduce virtual material texture and measure the users' ability to distinguish different virtual materials and to recognize the material class. Experimental results provide interesting details about tactile perception mechanisms and validate the adopted approach for tactile signals' recognition and material class discrimination.
Design of a Tactile Instrument to Measure Human Roughness Perception in a Virtual Environment
IEEE Transactions on Instrumentation and Measurement, 2000
This paper presents the experimental results on the measurement of human texture perception in virtual environments. The experiment is conducted with a haptic tactile instrument that provides sensations of rough textures directly to the fingertip of the users. It consists of a brush and a DC motor. The brush rubs directly against the user's fingertip. Simulated texture is felt through an aperture on the tactile actuator where the users place their fingertip. The speed and direction of the brush are varied to control the roughness of the virtual surface and to determine the effect of either variable on perceived roughness. The actuator is designed to be attached to an existing force feedback device in order to create an interface that can provide force feedback and tactile feedback. The magnitudes of rough textures are measured through this device by comparing the virtual textures with real sandpapers of different grit sizes. Through human factor testing, it is found that the direction of rotation has negligible effects on roughness perception when the time gap between two consecutive stimuli is as large as 10 s. However, when the time gap is reduced to 0.5 s, the effects of direction become prominent. The just noticeable difference with respect to speed is found to decrease as the base speed of the brush increases. The results also show that although each subject's perception of roughness is biased using various sandpapers, the measured data is divided between two trends. One group of users perceives the roughness to increase with increasing speed, while the other group perceives the roughness to decrease.
Finding Favorable Textures for Haptic Display
Haptic display is a powerful sensory medium to transfer information that gives a sense of haptic. We argue that giving haptic information positively affects only when the haptic makes a good impression. We examine the best materials that people feel pleasant to touch. Consequently, people prefer textures with uniform grain of brush, cotton clothes and silk. Throughout this paper, we propose a new approach to design of haptic display using tactile preference.